Pumping means for internal combustion engines



, Oct. 28, 1941. F. A. THAHl-:LD

PUMPING MEANS FOR INTERNAL coMEusTloN ENGINES Filed May 1'7,4 19:57

INVENTOR.

Ferl A. Tha/mld BY www ATTORNEY.

Patented Oct. 2s, 1941 UNITED STATES PATENT OFFICE PUMPING MEANS Fonm'rEaNAL vcomms- 'rioN ENGmEs corporation of Delaware Application May17, 1937, Serial No. 143,138

6 Claims. (Cl. 123-139) The object of this inventionis to provide avariable stroke for a fuel pump of an internal combustion engine. Or,more broadly, the object of the invention might be expressed as amechanism to 'govern the fuel intake port so that more or less fuelmight be allowe'd to enter the A of the fulcrum point |35 would merelyvary the stroke and the timing.

The invention, as shown by way of illustration in the drawing of thisapplication, embodies many of the essential features shown in the saidPatent 1,859,541, but one distinction of the present invention over thatshown in the said patent is that the upper surface of the lever |29 isnot concentric with the crank shaft and the cam mounted thereon, butinstead it slopes downwardly away from the fulcrum point, so that if thesaid lever is shifted to the right the plunger will be lowered and if ltis shifted to the left the plunger will be raised, partly closing theintake port for the fuel, but

the stroke will now be less` than in the firsty instance. Asa matter offact, when the lever is shifted to the right as far as it can be moved,the plunger will almost entirely uncover the intake port so' that amaximum amount of uid can pass into. the compression chamber of thepump, whereas, if the said lever is shifted as far as possible to theleft, the said intake port will almost entirely be closed, which wouldbe the idling position. Or, if desired, the slope of the cam surface onthe said lever can be made so that it would entirely close the intakeport so thatno fuel could enter.

Regardless of how the lever is shifted the said plunger wouldl alwaysreach substantially the same height, but it would move downwardlydifferent distances depending upon the position of the said lever.

Attention is called to the fact that when the plunger moves downwardly,a vacuum is created until the intake port is opened. The 'amount of lfully raised the said lever.

port depends upon the amount of intake port opening and duration of timethat is open.

Another object of the invention is to provide a by-pass in the upper endof the pump plunger so that while the plunger is being raised to itsmaximum position, the by-pass will allow the fuel vto be 4cut oil?before the actuating cam has This is extremely important, for thismechanism almost entirely eliminates the objectionable smoke that hasheretofore existed. This smoke is eliminated by having a sharp cut-offwhile the plunger is at maximum speed. It is desirable to spray the fuelinto the center of the air in the enginecylinder, and :then to cut oilthe spray before the actuating cam has completed the movement of theplunger. The by-pass is the means whereby this desirable result can beobtained. y

The invention may be more readily understood from the reading'of thefollowing specification and by referring to the accompanying drawing, inwhich I have shown by way of illustration, but not by way oflimitation',I several forms of the invention,y and wherein Fig. 1 is avertical view partly in cross section and is comparable to Fig. 9 ofsaid Patent 1,859,541.' Figs. 2, 2a, 2b,

.and 2c are cross sectional views,of the upper vided which is movable tothe right or. left as is fully shown and described in said Patent1,859,541. This lug |35 carries a fulcrum pin on which are mounted twolevers |29, connected by means of a cam web 2. The upper side of the web2 forms a cam surface 3 sloping gradually downwardly away from thefulcrum point or from point 23 to point 24. In other words, the highestpoint of l the cam surface is the point 23 nearest the fulcrum point,and the lowest effective part is the point 2l. |29 carry a pin l onwhich is mounted a roller |29', which roller rides on the periphery of aordinary practice,'as yis well known, the disc is4 provided lwith aplurality of such cams, usually four for aeronautical purposes.

fuel that can be drawnI in through the intake the surface 26 to thepoint 21 where the cam The levers l The roller, after reaching the point25 rides downwardly on 6 joins the surface 2i. The roller is now raisedby the cam surface 6, thereby elevating the plunger |26 giving it itspumping stroke.

The plunger |25 is slidable in a liner ||3 and is provided at its lowerend with a ange |34 and terminates in. a convex boss |28. A spring |33`is positioned between the ange |34 and a 'recess Il in the lower end ofthe pump barrel I|2. The boss |28 rides on the cam surface 3, and thespring |33 holds it in contact therewith.

As shown in the said Patent 1,859,541, therel is a ffuel pump designatedby the numeral |68 in 2 of said patent, which pumps fuel through a pipe|10 which leads to a T I I|, which is connected to the distributor pipesI2I. I employ similar pipes not shown which lead to a connection |22through which extend bores II, and in the jacket ||2 and communicatingwith the boresII is a circular channel I2, similar to the channel showninFig. 10 of the said patent. Fuel intake ports |3 extend through thejacket ||2 into the interior thereof.

The liner IIS is also provided with an annular passageway Il similar tothe channel' I2, and ports I5 extend through the liner H3 into theinterior of the compression chamber. 'I'he bores II are always full ofoil, and this oil passes into the' channel l2 through the ports |3 intothe peway vIl and through the ports I5 into the compression chamber of.the pump mech- Above Vthe liner IIS and within the jacket ||2 is astationary valve housing I6 provided with a bore I'I, 'and a valvemember I8 is seated at the upper end of the said bore, which valvemember is normally closed by means of a spring |l. When oil is pumped bythe plunger |25.. it f unseats the valve member I8 and forces oilupwardly through the e. f eway 99- which, as shown in the'said Patent1,859,541, communicatesvwith a'nozzle mechanism, best shown in Fig. 20of said patent, whereby the oil which has been pumped is sprayed into'the internal combustion chamber above the piston therein.

The upper portion of the pump plunger |26 is provided witha verticallyextending bore 2l,

l`which extends from the upper end of the said plunger downwardly toand?f communicates with a laterally extending pore-2|, whichcommunicates with anannular channel 22 in the pump plunger, the saidbores 2l and 2| and channel* 22 constituting a by-pass as willhereinafter be When the 1118435 is moved tothe position Awill assume theposition shown in Fig. 2 when roller reaches the point 21.' If, however,the

lever |29 should be shifted to the left of the position` shown in Eg. lor to the point 23, the Pump Pllmgl'. mately the positionshown in Fig.2a substaniallyclosingtheportlif,

AIt will therefore be apparent' that whenthe rollerisatthepoint2'ltheopening oftheA intakeportcanbevaried'firomwideopenpom-` tionto closedposition by merely'shifting the lever havingthecamsurfacel. Asbeforestated,

would be raised into approxi- Y the amount of fuel which will enterthrough the intake port I5 A*onLeach stroke will depend upon how much ofthe intake port is closed and also upon the length of the time thatitis-open,

5 which of course would depend upon the speed of the engine, If theylever |29 were, however, shifted as Ifar to the left as possible, theplunger would be raised -to an extent to entirely close the ports 10 I5,in which case no fuel would be pumped to the engine. f

If we desired the engine to idle, the lever |29 would be moved to theleft, from the position shown' in Fig. 1 almost to the point 23, so asto almost but not entirely to close the ports I5. Attention is called tothe fact that in order to eliminate smoke, I cut off the introduction offuel pumped while the plunger |26 is moving at high velocity.

inclusive, Fig. l2v shows the plunger in its depressed condition withthe lever |29 ,inapproximately the position shown in Fig. l, but withVthe point 21 of the cam d isc below the roller. Itl 25 willbenoted thatthe ports I5 are almost entirely opened.- If desired the cam can bearranged to entirely open. the ports.- When the roller |29 engages thecam 6 the plunger moved .upwardlyto substantially the positions 30 shownin Figs. 2a,'2b, and 2c. In Fig. 2a it will be noted that the ports I5are completely closed. No pumping action occurs until the ports I5 arecompletely closed and all pumping action will cease when the plunger hasreached the position shown in'Fig. 2b, and any `additional upwardmovement will cause the ports I5 to communicate with the channel 22 sothat the oil will pass downwardly into the channel 20 andcommunicatingchannels 2|, to the channel 22,

40 andthence out of the-ports I5, thereby relieving the pressure abovethe plunger so that no additional fuel is pumped. Even with the port I5completely opened, the space above the piston would not bey completelyiilled with fuel except in those cases where' the engine was stopped andI I' I with the port Iiiuncove'red. In normal running,

however, this spacel above the port would never 'be completely lled withoil even with the port entirely'opened for the port is too small toallow a sufiicient quantity of fuel to enter the space.

above the piston during the short period of time which it has to soenter. Obviously, much less fuel could enter when the port I5 is onlyminutely opened. In any case, however, the I6 pumping stroke commenceson the upward movement of the piston after it has entirely closed ,theport IS-but'this does not mean to say that the eifective part of thepump'stroke commences at that instant, that is, it does not follow that'fuel would commencefto pass by the valve I9 at the same instant thatthe piston completely closed the port I5. As a matter of fact, the

piston would have to move up a distance cor-v 'responding to the amountof the unfilled portion of the space above the piston before oil wouldstart passing by the valve I8. For instance, if this chamber above the'piston was half full of oil, the pistoi' would have to. move furtherthan if the said chamber was threei shown in- 2c, no fuel will bepumped. This means that the fuel -injection is' given a sharp cut-0115Vwhile the plunger ismoving at its. highest`ve- I accompnsh this resun-lby 20 providing alby-pass. Referring to Figs. 2 to 2c locity.

' the same,

plunger whenv thel lever If the by-pass above described were eliminatedso that theI fuel would continue to be injected while the plunger movedfrom the position shown in Fig. 2b to that shown in v1"ig.2c the lastpart of this movement would result in the slow injectionlof fuel intothe combustion chamber, which would mean that it would not be sprayedinto the combustion chamber, but a part at least thereof would simplydribble into which wouldresult in 'faulty combustion, which wouldproduce a'great quantity of smoke. This smoke is almostcompletely-eliminated by thecut-off above described.

It is obvious that many changes in the construction and details shown inthe drawings and described in the specification may be made withoutdeparting from the spirit of this invention, and I reserve the right tomake all changes and modifications which may fairly fall within lthescope of the appended claims. Having now described my invention, Iclaim:

1. In combination, a plunger, a lever having a cam surface contactingthe end of said plunger, the fulcrum of said lever being shiftabletowards or away from said plunger, a cam to operate said lever, al pumpbarrel 'having an intake port. said cam surface. serving as a means tionto partially close said is at the bottom of of said lever serving as ameans to delay the timing of the pumping stroke of said plunger, and aspring tending to move said plunger so as to open said port.

2. In a fuel pump having an intake port, a plunger, a spring tending tomove said plunger in one direction and a shiftable lever having a camsurface contacting said plunger, said spring and camsurface serving as ameans to adjust said plunger so as to close or open said port while theplunger is at port while the plunger pump, a camto actuate said pistonon its pumping stroke, and means to render the pump stroke ineffectiveduring the latter part of said stroke so as to make a sharp cut off.

3. In a combination, a pump barrel provided with an intake port, aplunger forming a piston, said piston having an annular channel and aby-pass leading from the upper end of the piston to said channel, thespace above the piston communicating with said port when the piston isat the end of its suction stroke and the channel being brought intocommunication with the port before the piston has completed its pumpingstroke, a lever provided with a cam surface contacting the plunger, acam to operate said lever, said lever being shiftable transversely ofthe contacting portion of said plunger so as to vary the its stroke, thesaid shiftingA timing when the plunger will be operated by said cam saidlever serving as a means to actuate the piston so as to vary the amountof opening of the port when the piston is at the end of its suctionstroke. y

4. In a combination, a pump barrel provided with an intake port, aplunger forming a piston, said piston having an annular channel and aby-pass leading from the upper end of the piston 'to said channel, thespace above the piston communicating with said port when the piston isat the end of its suction stroke andthe channel being brought intocommunication with the port before the piston has completed its pumpingstroke, a lever provided with a cam surface contacting the plunger, acam to .operate said lever, said lever being shiftable transversely ofthe contacting portion of said plunger so vas to vary the timing whenthe plunger will be operated by said cam said lever servingas a means toactuate the piston so as to vary the amount of opening of the port whenthe piston is at the end of its suction stroke.

5. In combination. a pump barrel provided with an intake port, a plungerforminga piston,

0 said piston having an annular channel and a .to move said? is shiftedin one directhe bottom of its stroke ac- .cording to the amountV of fuelit is desired to by-pass leading from the upper end of the piston r tosaid channel, the space above the piston communicating with said .portwhen the piston is at the end of its suctionstroke and the channel beingbrought into communication with the port before the" piston stroke, alever provided with a cam surface contacting the plunger, a cam'tooperate said lever, said lever being shiftable transversely of thecontacting portion of said plunger so as to vary the timing when theplunger will be operated by said cam and the effective throw of saidlever when operated by the cam said lever serving .as

a means to actuate the piston so as to vary the amount of opening of theport when the piston is at the end offits suction stroke.

6. In a fuel pump, la plunger, a lever having a cam surface 'contactingthe end of said plunger, the fulcrum of said leverl being shiftabletowards or away from said plunger, a cam to operate said lever, a pumpbarrel having an intake port, said cam surface serving as a means tomove said plunger when thel lever is shifted in one direction topartially close said port while the plunger is at the bottom ofitsstroke and a spring tending to move said plunger so as to open thesize of said port, even when fully open, being suiliciently small toprevent the fluid to be pumped from completely filling the pump barrelabove the piston when the plunger is operated at any normal speed.

' FERI A. THAHELD.

yhas completed its pumping said port,1

